Negotiators from Iran, the U.S., and five other world powers are back at the table today, resuming nuclear talks in Geneva. They're expected to focus on what limits on its nuclear program Iran is willing to accept in exchange for relief from painful economic sanctions imposed by the international community.

NPR's Peter Kenyon is in Geneva, and has this report.

PETER KENYON, BYLINE: Going into the talks, comments from the top Iranian and American diplomats made for a notable contrast. In Paris, Iran's foreign minister, Mohammad Javad Zarif, told the news channel France 24 that a nuclear deal could be struck this week.

(SOUNDBITE OF FRANCE 24 BROADCAST)

KENYON: Secretary of State John Kerry, meanwhile, was in Israel, in part to reassure America's jittery Mideast ally that the Obama administration hasn't gone soft on Iran. Kerry repeated his assurance that no deal is better than a bad deal. The incentive to reach a deal sooner rather than later is real. Iran's president, Hasan Rouhani, was elected with a mandate to rejuvenate the staggering economy by getting sanctions lifted.

Washington and its allies are keen on freezing Iran's capacity to enrich uranium before it gets any closer for having fuel for a nuclear weapon. A senior Obama administration official in Geneva says the international side is looking for a first step from Iran that includes verifiable moves to suspend parts of its nuclear program. In return, Iran would be offered limited, targeted and reversible sanctions relief. At an event sponsored by the Brookings Institution in Washington, veteran arms control expert Robert Einhorn said Iran needs to agree to freeze its nuclear program in place, or even roll it back somewhat, to allow time to negotiate a comprehensive agreement.

ROBERT EINHORN: The objective is to halt further advances in the program, so that while they're negotiating a comprehensive agreement, the Iranians are not capitalizing on the period by advancing the program. I think that is a strategic and a political imperative.

KENYON: But Iran will want significant sanctions relief, something the international side is unlikely to give in the first step. The administration official says none of the core architecture of the sanctions regime would be touched in the initial phase. One idea floated in Washington includes the phased release of some of Iran's frozen assets, providing currency to Tehran without dismantling any existing sanctions. Suzanne Maloney with the Saban Center for Middle East Policy says she'd be surprised if Tehran finds that acceptable, unless the country is far more desperate for hard currency than it's letting on.

SUZANNE MALONEY: I think it'll be a real test of how low their foreign exchange balance is, if they go for any piece of that. Because the idea that they would be rewarded with cash for cooperation doesn't really get at what Rouhani has promised and was elected to do, which is to restore Iran's ability to do business as usual.

KENYON: There are many ways these talks could fail, given the high level of suspicion on both sides. Iran's supreme leader, Ayatollah Ali Khamenei, said recently that he's not optimistic, because the U.S. can't be trusted to actually lift the most painful sanctions on the banking and oil sectors. Analyst Maloney says the U.S. Congress also has the power to derail the talks, simply by taking up new oil sanctions, while Iran is trying to win relief from the existing ones. That, she says, would convince Iran's leaders that diplomacy is a trap.

MALONEY: Fundamentally, they're always, I think, on alert that the international community and the United States is trying to pull one over on them. And if there's movement on new sanctions that would be, in effect, an oil embargo, this is exactly the sort of narrative that Khamenei appreciates.

KENYON: Still, observers say the latitude and protection Khamenei is giving Iran's nuclear negotiators is a sign that Iran genuinely wants a deal. The question is whether it's possible to craft one that both sides can live with. Peter Kenyon, NPR News, Geneva.

DAVID GREENE, HOST:

Now, there was debate over whether it would be possible to force Syria to destroy its chemical weapons. This morning, some progress reported. The Organization for the Prohibition of Chemical Weapons has seen video verifying that a weapons facility near the city of Aleppo, Syria has been destroyed. Amid the civil war, that area is too dangerous for weapons inspectors to actually visit. The agency says it has now verified that 22 of the 23 sites identified by the Syrian government are, in fact, destroyed. Inspectors do still have to form a plan to eliminate the chemical weapons stockpiles themselves. Transcript provided by NPR, Copyright NPR.